Camera modules such as still camera modules and digital camera modules can be combined with a wide range of electronic devices. Some camera modules include a lens module and an image sensor module aligned with one another. In some cases, the lens module includes a lens barrel, and one or more lenses assembled in the lens barrel.
The lens barrel may be held within a mount and rotated so as to move the lens barrel closer to or away from the image sensor. To facilitate such movement of the lens barrel, inner threads (e.g., on the inner surface of the mount) engage with threads on the outer surface of the lens barrel.
An example of such a module is illustrated in FIG. 1A and includes multiple lenses 10A, 10B, 10C. If the focus length of the lens stack deviates from a desired value, it can be adjusted by moving the lens barrel 16 vertically within the mount 18 along the z-axis. Even though the image sensor 12 and its active array area 14 generally have a rectangular shape when viewed along the z-axis, circular lenses 10A, 10B, 10C are used to facilitate focusing of light passing through the lenses onto the image sensor 12 (see FIG. 1B).